Cells - the basic units of living things: แบบฝึกหัด

A student is using a light microscope to observe a slide of plant cells. If the eyepiece has a magnification of \(10\times\) and the objective lens currently in use has a magnification of \(10\times\), what is the total magnification of the image seen by the student?

DNA contains the instructions that determine an organism's traits. How does the DNA in the nucleus of a cell perform this function?

In a scientific experiment, the nucleus of a human zygote is removed and replaced with a nucleus taken from a human sperm cell. If this modified cell then undergoes cell division to produce two daughter cells, which statement best describes the constancy of the genetic material in the resulting cells?

In the levels of organisation of living things, what is formed when different tissues work together to perform a specific function?

When preparing a specimen for observation under a light microscope, why is it necessary for the sample to be cut into an extremely thin slice?

When observing a specimen under a light microscope, what is the purpose of switching from a low-power objective lens to a high-power objective lens?

When observing plant cells and animal cells under a light microscope, which specific cellular structure should a student look for to differentiate between them, based on its function of providing structural support and a fixed shape?

Using the unifying concept of systems and organisation and the principles of cell differentiation, explain why a group of identical embryonic stem cells that only undergo cell division without differentiation can never develop into a functional human body.

A student uses a light microscope to observe a specimen. For the observation to be successful, the student must follow specific steps and identify key structures.

(a) Identify the instrument usually used to peel a thin layer of onion skin for the slide. (1 point)

(b) To increase the visibility of transparent cell structures, what process should the student perform using a stain like iodine? (1 point)

(c) Identify whether the low-power or high-power objective lens provides a wider field of view. (1 point)

Plant cells have several distinctive organelles that are not found in animal cells, which enable them to perform specific functions vital for their survival and the broader ecosystem.

a) Identify two organelles typically found in a plant cell but absent in an animal cell. For each, describe its specific function.

b) Explain why a plant cell needs a cell wall, while an animal cell does not.